CA1202498A - Safener compositions - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A herbicidal composition with reduced phytotoxic side effects which comprises a herbicidally active compound selected from the group consisting of phenoxy-phenoxycarboxylic acid-(C1-C4)-alkyl-esters, halogenobenzoxolyloxyphenoxy-carboxylic acid-(C1-C4)-alkyl esters, halogeno-benzthiazolyloxy-phenoxy-carboxylic acid-(C1-C4)-alkyl esters, pyridyloxy-phenoxy carboxylic acid-(C1-C4)-alkyl- and (C2-C4)-alkinyl esters, and 2-(N-ethoxybutyrimidoyl)-5-(2-ethylthiopropyl)-3-hhydroxy-2-cyclohexen-1-one, together with a dichlorophenoxyacetonitrile as the safener compound in an amount sufficient to reduce or suppress phytotoxic side effects of the herbicides.

Description

The present invention provides compositions having activity as safeners and containing dichlorophenoxyacetonitriles.
From the European Patent Application No. 31 938 substituted aryloxy(thio) alkancarboxylic acid nitriles and -amidoximes are known as antidotes or safeners for various types of herbicides.
Surprisingly it has been observed that dichlorophenoxy-acetonitriles, especially 3,4- and 3,5-dichlorophenoxyacetonitrile, exhibit advantageous properties as safeners if they are combined with a herbicide selected from the group consisting of phenoxy-phenoxycarboxylic acid-(Cl-C4)-alkylesters, pyridyloxy-phenoxy-carboxylic acid-(Cl-C4~-alkyl(or (C2-C4)-alkinyl)-esters, halogenobenzoxazolyloxy-phenoxycarboxylic acid-(Cl-C4)-alkylesters, halogenobenthiazolyloxyphenoxy-carboxylic acid (Cl-C4)-alkylesters and 2-(N-ethoxybutyrimidoyl)-5- (2-ethylthiopropyl)-3-hydroxy-2-cyclohexen-l-one.
Combined with herbicides of these types dichlorophenoxy-acetonitriles reduce or suppress the phytotoxic side effect of the above herbicides on use in crop plants at surp.risin~ly low doses.
Accordin~ly the present inventi.on provides a process for suppressing phytotoxi.c effects of herbicides towards crop plants, said herbicides being selected from the group consisting of phenoxy-phenoxycarboxylic acid-(Cl-C4)-alkyl esters, halogeno-benzoxazolyloxyphenoxy-carboxylic acid-(Cl-C4)-alkyl esters, halogenobenzthiazolyloxyphenoxy-carboxylic acid-(Cl-C4)-alkyl esters, p~ridyloxy-phenoxy carboxylic acid-(Cl-C4)~alkyl- and (C2-C4)-alkinyl esters, and 2-(N~ethoxybutyrimidoyl)-5-(2-ethylthiopropyl)-3-hydroxy-2-cyclohexen-1-olle, which comprises treating the crop plants, or the soil on which such plants grow, wi.th a dichlorophenoxyacetonitrile as the safener compound before, after or simultaneously with the herbicide.
From the above named herbicides the following are of special interest:
~-[4-(2,4-dichlorophenoxy)-phenoxy]-propionic acid methyl ester (Hl), ~-[4-(6-chlorobenzoxazol-2-yloxy)-phenoxy]-propionic acid ethyl ester (H2) ~
~ ~-(3,5-dichloropyridyl-2-oxy)-phenoxy]-propionic acid prop-2-inyl ester (H3), ~-[4-(5-trifluoromethylpyridyl-2-oxy)-phenoxy]-propionic acid butyl ester (H4), ~-[4-(3-chloro-5-trifluoromethylpyridyl-2-oxy)-phenoxy] propionic acid methylester (H5), ~-[4-(6-chlorobenzthiazol 2-yloxy)-phenoxy]-propi.onic acid ethylester (H6) ~-[4-(trifluoromethylpyridyl-2-oxy)-phenoxy]-propionic acid methyl ester (H7) and - la -

2-(N-ethoxybutyrimidoyl)-5-~2-etllylthiopropyl)-3-hydroxy-2-cyclohexen-1-one ~18) or their optical isomers.
Phytotoxic side effects of the crop plants caused by these herbicides are decreased drastically when mixed with dichlorophenoxyacetonitriles, especially 3,~-and 3,5-dichlorophenoxyacetonitriles, so that the tolerability of the herbicides is considerably increased while their activi~ies against the weeds remain unchanged. No antagonistic effects of the safeners are observed.
The quantitative ratio of safener to herbic~de may vary within wide limits of from 0.01 to 10 parts, especially 0.1 to 1 parts of safener per part of herbicide. The optimum herbicide/safener proportion depends on the particular type of herbicide and the kind of plant population to be treated and can be determined according to the circumstances by corresponding tests.
Dichlorophenoxyacetonitriles can be used for pretreating ~disinfecting) the seeds or cuttings of the crop plants, they may be applied to the furrows before sowing or pre- or post-emergent in the form of tank mixtures (the pre-emergence process including treatment of the area under cultivation before and after sowing). In principle, the safeners can be used before1 after or simultaneous Wit]l the herbicide; preerred, however, is simultaneous application in the form of tank mixtures or ready-for-use formulations.
The safeners or the safener/herbicides mixture may be formulated as wettable powders, emulsifiable concentrates, dispersions, dusting agents, granules or sprayable solutions, and they optionally contain suitable carriers such as wetting agents, emulsifiers, adhesives, dispersing agents, solid or liquid inert substances, carriers, grinding auxiliaries and solvents.
Wettable powders are preparations which can be dispersed homogeneously in water and which, besides the active compound and apart from a diluent or inert substance, if appropriate, also contain wetting agents, for example polyoxyethylated alkylphenols, polyo~yethylated oleyl- or stearylamines, alkylsulfonates or alkylphenylsulfonates, and dispersing agents, for example sodium ligninsulfonate, sodium 2,2'-dinaphthylmethane-6,6'-disulfonate, sodium dibutylnaphthalenesulfonate or sodium oleoylmethyltauride.
Emulsifiable concentrates can be prepared, for example, by dissolving the active compound in an organic solvent, for example butanol, cyclohexanone, dimethylformamide, isophorone or high-boiling aromatic solvents, with the addition of one or more emulsifiers. The following are examples of emulsifiers which can be used: calcium alkylarylsulfonates, fatty acid polyglycol esters, alkylaryl polyglycol ethers, fatty alcohol polyglycol ethers, polyoxyethylated oleyl- or stearylamines, propylene oxide/ethylelle oxide condensation products, alkyl polyethers, sorbitan fatty acid esters, alkylaryl/propylene oxide/
ethylene oxide condensation products, etc.
Dusting agents can be obtained by grinding the active compound with finely divided solids, for example talc, natural clays, such as kaolin, bentonite or pyrophillite, or diatomaceous earth.
Granules can be prepared either by atomizing a solution of the active compound onto an adsorbent granulated inert material, or by applying active compound concentrates by means of binders, for example polyvinyl alcohol, sodium polyacrylate, methylhydroxyethyl cellulose or mineral oils~
to the surface of carriers, such as sand, kaolinite or granula~ed inert material. Suitable active compound formulations can also be prepared in the manner customary for the production of fertilizer granules - if desired as a mixture with fertilizers.
The total amount of active substance in the formulations ready ~o be marketed is preferably about 2 to 95, more preferably 5 to 80 weight %, ~2~2~

t}lC remainder Up to 100o consisting of customary formlllatlon auxili.aries such as adhesives, wetting agents> emulsifiers, dispersing agents, fillers, solvents and carriers.
In wettable powders, the total concentration of the safener is preferably in the range of from about 10 to 80 weight %, the remainder up to 100% consisting of usual formulation auxiliaries; in the case of emulsifiable concentrates, it is in a range of about 10 to 70 weight %. Sprayable solutions contain about 2 to 20 weight % of active substance mixture. In the case of granules, the total active substance content is about 2 to 10 weight ~, and dust formulations contain about 5 to 20 weight % of active substance mixture.
Subject of the present invention are thereore also herbicidal compo-sitions containing from 2 to 95, preferably 5 to S0 weig}lt % of an active sub-stance combination of safener and herbicide; the remainder up to 100% consisting of customary formulation auxiliaries.
For application, the concentrates optionally are diluted in a customary manner, for example with water in the case of wettable powders, emulsifiable concentrates and dispersions. Formulations in the form of dust and granules and sprayable solutions are usually not diluted further with other inert substances before use.
zo Depending on external conditions such as temperature, moisture etc.
the required application concentration of the safener/herbicide compositions according to the invention varies within wide limits and is generally from 0.1 to 3, preferably 0.2 to 1.5, kg/ha of active substance combination.
Tlle following examples illustrate the invention.
A. Formula~ion Examples 1 to 3 1. A concentrate/readily emulsifiable in water is obtained from 25 weight % of 3,4-dichlorophenoxyacetonitrile, 50 weight % of xylene, 8 weight % of the calcium salt of dodecylbenzene-sulfonic acid, 4 weight % of ethoxylated castor oil (40 E0) and 4 weight % of ethoxylated nonylphenol (10 E0).
The active ingredient is dissolved in the quantities of solvents indicated, while stirring and slightly heating, and the emulsifiers are added subsequently ~o the solution obtained~ Stirring is continued at slightly elevated temperatures until the solution is clear and free from striae.
2. A readily emulsifiable concentrate of a herbicide and the safener ~100 : 1) in water is obtained from 12.00 weight % of ~-L~-(6-chloro-benzoxazol-2-yl-oxy)-phenoxy~-propionic acid ethyl ester, 0.12 weight % of 3,4-dichlorophenoxyacetonitrile, 70.00 weight % of xylene, 7.88 weight % of the calcium salt of dodecylbenzene-sulfonic acid, 6.00 weight % of ethoxylated nonylpllenol (10 E0), 4.00 weight % of ethoxylated castor oil ~40 E0).
The preparation is carried out analogously to that in Example 1.

3. A concentrate of a herbicide and the safener ~1 : 10) readily emulsifiable in water is obtained from

4.0 weigilt % of f4-~6-clllorobenzoxazol-2-yl-oxy)-phenoxy~-propiollic acid ethyl ester, 40.0 weight % of 3,4-dichlorophenoxyacetonitrile 30.0 weight % of xylene, 20.0 weight % of cyclohexanone, 4.0 weight % of the calcium salt of dodecylbenzene-sulfonic acid, 2.0 weight % of ethoxylated castor oil ~40 E0~.

The preparatlon is carried out analogously to Example 1.
B. Biological Examples E X A M P L E
Seed of weed grasses (wild oats ~AVF) and black grass ~ALM)) and of wheat ~TA) was sown in plastic pots of 9 cm diameter on sandy loam. The pots were placed in a greenhouse and kept under favourable growth conditions.
The plants in the three-leaf stage were treated with the herbicides H2, H3 and with the safener Al alone and with their co}nbinations at different weight ratios and doses given in the Table below in ~he form of aqueous suspensions or emulsions using a quantity of water corresponding to 600 l/ha ~tank mix process). After about 3 weeks in the greenhouse, the damage of the plants was evaluated visually in comparison with untreated controls. The results are listed in Table 1.

Table 1 Product Dose herbicidal activity in percent kg a.i./ha TA AVF ALM
-2 2.0 50 100 100 1.0 ~5 100 100 0.5 35 99 100 0.25 30 75 9&

0.125 10 10 20 ~2~

Table 1 Product Dose herbicidal activit~ in percent kg a.i./ha TA AVF ALM

H3 2,G 100 100 100 1.0 98 100 100 0.25 10 95 98 0.125 0 20 20 A1 0,2 10 0 0 0.1 0.05 - 0 0 0 ~2 + A1 2.0 ~ 0.2 10 100 100 1.0 + 0.2 10 98 100 ~.5 + 0.2 0 97 100 0.25 + 0.2 0 go 9~
0.125 + 0.2 0 35 20 H3 + A1 2~0 + 0.1 ~ 10 100 100 1.0 + 0.1 10 99 100 0.5 ~ 0.1 10 9~ 100 0~.25 + 0.1 5 ~5 88 0.125 + 0.1 0 30 80 ~2 + A1 2.0 ~ 0.05 35 100 100 1.0 ~ 0.05 30 100 100 0.5 + 0.05 15 100 100 0.25 ~ 0.05 o 70 93 0.125 + C.05 0 35 83 ~2~
.
Table l Product Dose herbicidal activity in percent kg a.i./ha TA AVF ALM

H3 + A1 2--0 ~ 0.2 85 100 100 1,0 + 0.2 74 100 100 O.S + 0.2 35 100 100 0.25 + 0.2 0 97 100 0.125 ~ 0.2 0 83 88 H3 + A1 2~0 + 0.1 100 100 100 1.0 + 0.1 85 100 100 0.5 + 0.1 45 100 100 0,25 + 0.1 10 98 100 . 0.125 + 0.1 10 83 89 H3 + A1 2-0 + 0.05 100 100 100 1.0 + 0.05 75 100 100 0,5 ~ 0.05 25 100 100 0.25 + 0.05 ~ 10 99 100 0.125 + 0.05 10 40 83 ~1~ \)-- ~ 0-_H-COOC2EI5 Cl CH3 Cl CE13 H3 =Cl ~ o ~ O-CH-COOCH2C_CH

- Al = 3,4-dichlorophenoxyacetonitrile Abbreviations - TA = wheat (Triticu~ aestivum) AVF = wild oat (Avena fatua~
ALM = blackgrass (Alopecturus myosuroides) As shown in Table 1, the herbicides H2 and H3 considerably damaged the wheat plants (TA), whereas the safener Al caused practically no damage in wheat plants or in the weed grasses tested. The mixture of the herbicides H2 or H3 together with the safener, causes a drastic reduction of the phytotoxicity, of the herbicides towards the crop plant. The damage in wheat, on admixture of the safener, is either suppressed completely or reduced to a level acceptable from an economic point of view.
A comparison of the activities of ti1e herbicides against the weedgrasses shows that no noticeable loss in activity, i.e. antagonistic effect, occurs on addition of the safener. Hence, the saener tested is very suitable for considerably improving the compatibility of the herbicides 112 or H3 with crop plants and enabling these herbicides to be used for selectively combattil1g weedgrasses in wheat.

lhe test plants were grown and treated with the herbicides and the safener, and evaluated as in Example 1. In the present case there were used the herbicides Hl and H2 alone or together with the safener Al (tank mix).
The test plants used were winter-wheat ~TA-W), winter-barley (HV), annual black-grass ~ALM) and wild oats (AVF). The test results are su~ arized in Table 2.
Table 2 Product Dose herbicidal activity in percent kg a.i./ha TA-W HVALM AVF

H2 0 5 65 lO098 lO0 0.2 40 9890 lO0 0.12 35 9585 lO0 0.06 25 8880 lO0 0.03 0 5550 85 ~%~

Table 2 Product Dosc herbicidal activity in percent kg a.i./ha TA-W HV ALM AVF
.
H1 2.0 - 25 - 93 1.0 . - 20 - 85 0.5 - 15 - 70 0.25 _ 0 _ ~5 0.125 _ o _ 10 A1 0.12 0 0 0 0 H2 + A1 0 5 ~ 0.12 10 55 100 100 0.25 ~ 0.12 S 45 93 100 0.12 + 0.12 0 30 90 85 0.06 ~ 0.12 0 20 75 90 0.03 ~ 0.12 0 5 40 60 H1 + A1 2.0 + 0.12_ 15 - 90 1.0 * 0.12 - 5 - 83 C.5 ~ 0.12 - 0 - 70 0.25 + 0.12 - 0 - '10 0.125 ~ 0.12 - 0 - 20 ~1) H2: see Ex. 1 H1 = C1 ~ O ~ CH-COOCE13 Cl _~breviation~:
TA-W = Triticum aestivum ~winter-wheat) HV = Hordeum vulgare (winter-barley) ALM = Alopecurus myosuroides AVY = Avena fatua a.i.. = ac~ive ingre~ient - = not tested ~Z~2~

As can be seen from the resu]ts in Table 2, the phytotoxicity of the herbicides IIl to barley and H2 to wheat is reduced by addition of the safener while the activity against weedgrasses of the herbicides is not influenced by antagonistic effects.

Seed of spring-wheat (TA) and spring-barley (HD) was sown in the open air. When the crop plants in the three-leaf stage were up to the tillering stage, they were treated with the herbicides Hl, H2 and the safener Al, alone and in combinations thereof (in the form of emulsion concentrates) at different doses. The products were applied in the form of aqueous emulsions using a quantity of water of 400 l/ha. The weed grass, ~Y]IiC}I could be observed before treating the crop plants, was annual blackgrass.
The test plots had a size of 10 and 11.25 m2, respectively. The tests were repeated three times. The damage to the crop plants was evaluated visually at 24 days (barley) and 28 days (wheat) after the treatment. The results are listed in the following Table 3.
Table 3 Product Dose herbicidal activity in percent kg a i./ha IID TA ALM
-Al 0.18 0 0 0 H2 0.18 - 13 99 0.27 - 18 100 H2 + Al 0.18 + 0~09 - 0 100 0.27 + 0.13 - 0 100 0.36 ~ 0.18 - 0 100 2~

Table 3 Product Dose herhicidal activity in percent kg a.i./ha HD TA ALM

Hl 0.72 6 - -0.90 17 1.80 32 Hl * Al 0.72 * 0.1 0 0.90 ~ 0.13 0 - -1.80 + 0.25 4 Hl, H2, Al see Examples 1 and 2 Abbreviations:

HD = Hordeum distichum ~spring-barley) TA = Triticum aestivum (spring-wheat) ALM = annual blackgrass As shown in Table 3, barley is no longer damaged by the herbicide Hl, and wheat is no longer damaged by the herbi~ide H2, in the presence of the safener Al. However, these herbicides remain active against the annual blackgrass.

. .
The test plants were grown to the four to five-leaf stage in a green-house and were then treated with tlle herbicides El2' ~active D~) form of herbicide H2 of Example 1) H4 to H8 and with the safeners Al and A2 alone and with the combinations of the herbicides and the safeners ~tank mix) at the doses given below in Table 4.
After about 3 weeks in the greenhouse, the damage to the crop plants was evaluated visually in comparison with the untreated con~rols. The rasults are listed in Table 4.

Table 4 Product Doseherbicidal activity in percent kg a.i./ha TA HV SV ZM OS
. .
~4 0.1S 60 - 75 H4 + A1 0 25 10 - _ A1 0.25 0 - 0 ~

H5 0.08 65 70 - - -H5 i~ A2 0 25 15 2 0.25 0 .
H6 0.60 - - - 65 30 6 2 0.60 + _ _ _ 15 0 0.50 A2 0~50 _ _ _ O o H7 0.15 - - 95 - 25 H7 + A1 0.15 + - - 35 - 0 0.25 A1 0.25 - - 0 H8 0.25 . 70 - - - 45 H~ + A2 0 50 10 - - ~ 5 H2' 0.60 25 50 - - -H2l + A1 0.60 + . 0 5 0.50 .. . ...

~202~g~

Abbreviations:
~ .

TA = wheat A1: see Ex. 1 - 3 HV = barley A2: 3,5-dichlorophenoxy-SV = sorghum acetonitrile ZM = corn OS = rice = CF3 ~ o ~ o-C~-~OO(CH2)3-CH3 H5 F3C ~ o ~ ,H3 . C~13 Cl~ \~- O ~ O-CH-COOC2H5 H7 = CF3 ~ ~ ' 3 l ~ 2 5 H~ = ~ 3 7(n) /
Cll \

S~

~Z~92~a~

As shown in Table 4 the herbicides H2' and 11~ to H8 alone considerably damage the crop plants whereas the safeners Al and A2 alone cause no damage.
The mixture of the herbicides together with the safeners causes a drastic reduction of the phytotoxicity of the herbicides towards the crop plants while still preserving the desired herbicidal activi.ty towards the undesired species.

Claims (22)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS.

1. A process for suppressing phytotoxic effects of herbicides towards crop plants, said herbicides being selected from the group consisting of phenoxy-phenoxycarboxylic acid-(C1-C4)-alkyl esters, halogenobenzoxazolyloxy-phenoxy-carboxylic acid-(C1-C4)-alkyl esters, halogenobenzthiazolyloxy-phenoxy-carboxylic acid-(C1-C4)-alkyl esters, pyridyloxy-phenoxy carboxylic acid-(C1-C4)-alkyl- and (C2-C4)-alkinyl esters, and 2-(N-ethoxybutyrimidoyl)-5-(2-ethylthiopropyl)-3-hydroxy-2-cyclohexen-1-one, which comprises treating the crop plants, or the soil on which such plants grow, with a dichloro-phenoxyacetonitrile as the safener compound before, after or simultaneously with the herbicide.

2. A process as claimed in claim 1 wherein from 0.01 to 10 parts by weight of the safener is used per part of the herbicide.

3. A process as claimed in claim 1 wherein from 0.1 to 1 part by weight of the safener is used per part of the herbicide.

4. A process as claimed in claim 1, 2 or 3 wherein the safener compound is 3,4-dichlorophenoxyacetonitrile.

5. A process as claimed in claim 1, 2 or 3 wherein the safener compound is 3,5-dichlorophenoxyacetonitrile.

6. A process as claimed in claim 1 wherein the herbicide is .alpha. - [4-(2,4-dichlorophenoxy)-phenoxy]-propionic acid methyl ester, .alpha.- [4-(6-chlorobenzoxazol-2-yloxy)-phenoxy]-propionic acid ethyl ester, .alpha.- [4-(3,5-dichloropyridyl-2-oxy)-phenoxy]-propionic acid prop-2-inyl ester, .alpha.-[4-(5-trifluoromethylpyridyl-2-oxy)-phenoxy]-proppionic acid butylester, .alpha. -[4-(3-chloro-5-trifluoromethylpyridyl-2-oxy)-phenooxy] propionic acid methylester, .alpha. -[4-(6-chlorobenzthiazol-2-yloxy)-phenoxy]-propioniic acid ethylester, .alpha. -[4-(4-trifluoromethylpyridyl-2-oxy)-phenoxy]-propiionic acid methyl ester, or 2-(N-ethoxybutyrimidoyl)-5-(2-ethylthiopropyl)-3-hhydroxy-2-cyclohexen-1-one, or an optical isomer of any such compound.

7. A process as claimed in claim 6 wherein from 0.01 to 10 parts by weight of the safener is used per part of the herbicide.

8. A process as claimed in claim 6 wherein from 0.1 to 1 part by weight of the safener is used per part of the herbicide.

9. A process as claimed in claim 6, 7 or 8 wherein the safener compound is 3,4-dichlorophenoxyacetonitrile.

10. A process as claimed in claim 6, 7 or 8 wherein the safener compound is 3,5-dichlorophenoxyacetonitrile.

11. A process as claimed in claim 1,2 or 3 wherein the crop plant is a grain cereal.

12. A process as claimed in claim 6, 7 or 8 wherein the crop plant is a grain cereal.

13. A herbicidal composition with reduced phytotoxic side effects which comprises a herbicidally active compound selected from the group consisting of phenoxy-phenoxycarboxylic acid-(C1-C4)-alkyl-esters, halogenobenzoxazolyloxy-phenoxy-carboxylic acid-(C1-C4)-alkyl esters, halogenobenzthlazolyloxy-phenoxy-carboxylic acid-(C1-C4)-alkyl esters, pyridyloxy-phenoxy carboxylic acid-(C1-C4)-alkyl-and (C2-C4)-alkinyl esters, and 2-(N-ethoxybutyrimidoyl)-5-(2-ethylthiopropyl)-3-hydroxy-2-cyclohexen-1-one, together with a dichlorophenoxy-acetonitrile as the safener compound in an amount sufficient to reduce or suppress phytotoxic side effects of the herbicides.

14. A herbicidal composition according to claim 13 wherein the safener compound is 3,4-dichlorophenoxyacetonitrile.

15. A herbicidal composition according to claim 13 wherein the safener compound is 3,5-dichlorophenoxyacetonitrile.

16. A herbicidal composition according to claim 13, 14 or 15 wherein the amount of the dichlorophenoxyacetonitrile is from 2 to 95%.

17. A herbicidal composition according to claim 13, 14 or 15 wherein the amount of the dichlorophenoxyacetonitrile is from 5 to 80%.

18. A herbicidal composition as claimed in claim 13 wherein the herbicide is .alpha. - [4-(2,4-dichlorophenoxy)-pllenoxy]-propiollic acid methyl ester, .alpha. -[4-(6-chlorobenzoxazol-2-yloxy)-phenoxy]-propionicc acid ethyl ester, .alpha. - [4-(3,5-dichloropyridyl-2-oxy)-phenoxy]-propionic acid prop-2-inyl ester, .alpha. -[4-(5-trifluoromethylpyridyl-2-oxy)-phenoxy]-propiionic acid butyl ester, .alpha. -[4-(3-chloro-5-trifluoromethylpyridyl-2-oxy)-phenooxy]-propionic acid methyl ester, .alpha. -[4-(6-chlorobenzthiazol-2-yloxy)-phenoxy]-propioniic acid ethyl ester, .alpha. -[4-(4-trifluoromethylpyridyl-2-oxy)-phenoxy]-propiionic acid methyl ester,or 2-(N-ethoxybutyrimidoyl)-5-(2-ethylthiopropyl)-3-hydroxy-2-cyclohexen-1-one, or an optical isomer of any such compound.

19. A herbicidal composition as claimed in claim 18 wherein from 0.01 to 10 parts by weight of the safener is used per part of the herbicide.

20. A herbicidal composition as claimed in claim 18 wherein from 0.1 to 1 part by weight of the safener is used per part of the herbicide.

21. A herbicidal composition as claimed in claim 18, 19 or 20 wherein the safener compound is 3,4-dichlorophenoxyacetonitrile.

22. A herbicidal composition as claimed in claim 18, 19 or 20 wherein the safener compound is 3,5-dichlorophenoxyacetonitrile.